[Dovecot] help with basic setup

[Perish Mutyanda]

I am new to dovecot and would like to setup dovecot with mysql auth. I successfuly installed postfix admin and used the default
table structure there, Mail delivery works fine as It gets delivered to mailboxes. My problem is the login, dovecot runs with no errors
but I get the error: 
Mar 14 14:39:43 itecsouth dovecot: auth-worker(default): mysql: Connected to localhost (postfix)
Mar 14 14:40:34 itecsouth dovecot: pop3-login: Disconnected: rip=41.xxx.xxx.190, lip=41.243.140.153
Mar 14 14:41:14 itecsouth dovecot: pop3-login: Login failed: Plaintext authentication disabled: rip=41.xxx.xxx.190, lip=41.xxx.xxx.153
Mar 14 14:41:14 itecsouth dovecot: pop3-login: Disconnected: rip=41.xxx.xxx.190, lip=41.xxx.xxx.153
I have tried to change the pass scheme in dovecot-mysql.conf to CRYPT as but says unknown auth_scheme

a copy of my dovecot.conf
protocols = pop3
listen = *
login_process_size = 64
default_mail_env = maildir:/usr/local/virtual/%d/%u/
mail_extra_groups = postfix
verbose_proctitle = yes
first_valid_uid = 125
first_valid_gid = 125
mbox_read_locks = fcntl
mbox_write_locks = fcntl
protocol pop3 {
  pop3_uidl_format = %08Xu%08Xv
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
}
auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
auth_debug = yes
auth_verbose = yes
auth default {
passdb sql {
        args = /usr/local/etc/dovecot-mysql.conf
  }
userdb sql {
        args = /usr/local/etc/dovecot-mysql.conf
  }
}

-- and the dovecot-mysql.conf

# Database driver: mysql, pgsql
driver = mysql
default_pass_scheme = PLAIN
connect = host=localhost dbname=postfix user=dovecot password=dovecot
password_query = SELECT password FROM mailbox WHERE username = '%u' AND active = '1'
user_query = SELECT maildir, 125 AS uid, 125 AS gid FROM mailbox WHERE username = '%u' AND active = '1'